Commit fe78fcc8 authored Jul 17, 2015 by Eric W. Biederman

mnt: In detach_mounts detach the appropriate unmounted mount



The handling of in detach_mounts of unmounted but connected mounts is
buggy and can lead to an infinite loop.

Correct the handling of unmounted mounts in detach_mount.  When the
mountpoint of an unmounted but connected mount is connected to a
dentry, and that dentry is deleted we need to disconnect that mount
from the parent mount and the deleted dentry.

Nothing changes for the unmounted and connected children.  They can be
safely ignored.

Cc: stable@vger.kernel.org
Fixes: ce07d891 mnt: Honor MNT_LOCKED when detaching mounts
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

parent f2d0a123

fs/namespace.c

+2 −5

Original line number	Original line	Diff line number	Diff line
	@@ -1565,11 +1565,8 @@ void __detach_mounts(struct dentry *dentry)
	while (!hlist_empty(&mp->m_list)) {		while (!hlist_empty(&mp->m_list)) {
	mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);		mnt = hlist_entry(mp->m_list.first, struct mount, mnt_mp_list);
	if (mnt->mnt.mnt_flags & MNT_UMOUNT) {		if (mnt->mnt.mnt_flags & MNT_UMOUNT) {
	struct mount p, tmp;		hlist_add_head(&mnt->mnt_umount.s_list, &unmounted);
	list_for_each_entry_safe(p, tmp, &mnt->mnt_mounts, mnt_child) {		umount_mnt(mnt);
	hlist_add_head(&p->mnt_umount.s_list, &unmounted);
	umount_mnt(p);
	}
	}		}
	else umount_tree(mnt, UMOUNT_CONNECTED);		else umount_tree(mnt, UMOUNT_CONNECTED);
	}		}

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